Refrigerator control and alarm system



Nov. 29, 1949 c. w. KUHN 2489906 REFRIGERA'I'OR CONTROL AND ALARM SYSTEM Filed Ost. 15. 1945 4 erremnenraz n:wpse 47026 cavrm smrcu Patented Nov. 29, 1949 UNITED STATE 2489906 REFRIGERATOR CONTROL AND ALARM SYSTEM Clarence W. Kahn,

Cutler-Hammer, poration o! Delaware Wauwatosa, Wis., asslgnor to lnc., Milwaukee, Wis. a eur- Application October 15, 1945, Serial No. 622,435 3 Claims. (C1. 1 77-311) v 1 This invention relates to refrigerator control systems and while not limited thereto is particularly appllcable to alarm control systems for electric refrigerators of the type commonly known as home freeZers.

It is desirable that refrigerators of various types and particularly home freezers be equipped with an alarm control device which operates under abnormal temperature conditions within lzhe freezing compartment to indicate that the refrigerator is 'not functioning properly and requires attention. The present invention has among its objects 130 provide a simple and reliable alarm control device for this purpose.

Another object is to provide a unitary alarm control device for the above purpose which is complete in itself and is provided with a pressure responsive operating element of the gas containing type.

Another object is to provide an alarm control device of the aforesaid type which is responsiVe to operate a Signal either upon a predetermined abnormally high or a predetermined abnormally low temperature within the freezlng compartmenl: and is also responsive to operate the signal upon failure of its associated operating element.

Another object is to provide an alarm control device of the aforesaid character which is readily adjustable to provide for operation thereof at seleCted high and low abnormal temperature values within the freezing compartment and which is also provided with an Off-On control for rendering the same operative or inoperative, as desired.

Another objecl: is to device of the aforesaid type which is capable of being associated with an adjustable cold control device of the type ordinarily employed in connection with electric refrigerators to provide for actuation of the Oft-x1 control element by means of a cold control adjusting knolo associated with the cold control device.

Another object is 110 provide an "OfI-On cantrol of the aforesaid character which prevents restoration of the alarm control device to operative condition after an abnormally high temperature oonclition until the temperatum in the freezing compartmenl; drops 130 a given normal value.

Various other-objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that various modifications may be made in the embodiment illusprovide a unitary control trated without departlng from the spirit and scope of the appended clairns.

In the drawing,

Figure 1 illustrates an alarm control device embodying the invention in connection with an adjustable cold control device of a type commonly employed in the control of electric refrigerators;

Fig. 2 schematically illustrates the alarm control device shown in Fig. 1 with the cont rol mechanism thereof in an operative condition and.

Fig. 3 schematically illustrates the alarm cantrol device in an inoperative condition.

Referring to Fig. l, reference character l designates an alarm control device embodying the invention which is shown in connection with an automatic temperature control device 2 of the type disclosed in the patent 'to C. F. Robbins N0. 2375387 issued May 8, 1945. These davices are both secured to a front platze 3 to proVide a unitary assembly. Device 2 is adapted to maintain the temperature within the freezing compartment of an electric freezer between given upper and lower working limits which are determined by the setting of a rotatable adjusting knob and as herelnafter set forth device l operates upon an abnormally high or an abnormally low temperature condition within the refrigerating chamber actuate a signal which may be seither audible or visible to indicate that the freezer is not functioning properly and requ1res attention. Also as herelnafter sei; forth the alarm control device I is provided with an Ofi-On control which is operable by the cold control knob 4 assoc iated with device 2 'to render lahe alarm control device operative or inoperative as desired.

As schematically illustrated in Fig. 2, alarm c0'xitrol device l is provided with a switch mechanism comprising spaced upper and lower spring contact fingers 5 and 6, and. an intermediate spring contact finger l. These contact fingers are mounted wlthin an insulating casing 8 and each is fixed at one end to said casing. The free end of upper contact finger 5 is biased to move downwardly and is normally maintained in engagement with an adjustable screw stop 9, and the free end of lower contact finger 6 is biased to move upwardly and is normally maintained in engagement with an adjustable screw stop H]. The free end of intermediate contaot finger l is biased to move downwardly and as will now be sei: forth said finger is controlled by a gas containing operating element lll having a loading spring l2 assoclateol therewlth.

Operating element H comprises a rigid cup member l? having a closed taube extension M on" the bottom wall thereof, and a. flexible metal diaphragm I sealed within said cup member. Diaphragm I5 1s spaced With respect 120 the bottom wall of cup member I3 to provlde a closed chamber I6 and said chamber and tube extension I4 are filled with a fluid such as propane. The open end of cup member I3 is provided with a fiange projection which is fixed to the under side of casing 8 and loading spring I2 is interposed between said casing and diaphragm I5. Loading spring I2 comprises an elongated leaf spring member which is supported at opposit e ends by a projectioh I'I and an adjustable stop I8 on the under side of casing 8. Loading spring I2 engages disk I9 on the upper side of diaphragm I5 to subject said diaphragm I:o a downward loading pressure. The intermediate contact finger l 1s operatively connected to operating element II by a vertically disposed insulating bar 20 havlng a projection 2I for engaging the under side of said finger. Bar 20 is slidably supported at its upper end within a recess in casing 8 and upward movement thereof is limited by an adjustable screw stop 22. The lower end of bar 20 is held in engagement with the upper side of loading spring I2 under the biasing action of contact finger I.

Contact fingers 5, 6 and I are connected as shown in Fig. 2 to control a signal circuit 23 including a sigma! device such as an electric hell 24. Also as shown in Fig. 2 taube extension I4 of operating element II is arranged within the freezing compartment 25 of an electric freezer 26 which is inclicated by dotted lines, and I:he automatic temperature control device 2 is provided with a gas fillecl operating element 27 having a tube extension 28 which is also located within said compartment. Temperature control device 2 is controlleii by its associated operating element 21 to automatically maintain the temperati1re within the freezing compartment between selected upper and lower working limits which are determined by the setting of knob 4. As will now be sei; forth, alarm control device I is automatically controlled by its associated operating element II to provide for actuation of alarm 24 either upon an abnormally high or an abnormally W temperature condition within compartment 22 or upon failure of pressure in said operating element. c

Loading spring I2 is adjusted by its associated stop I8 so that intermediate contact finger I is maintained midway between the upper and lower contact fingers 5 and 6 when the temperature in compartment 25 is at a given normal operating value. When the temperature in compartment 25 rises above said normal operating value, diaphragm I5 moves upwardly againsb the action of loading spring I 2 to move contact finger 7 toward upper contact finger 5, and when the temperature in said compartment drops below said no mal operating value said diaphragm moves downwardly under the action of said loading spring to permit biased movement of contact finger I toward lower contact finger 6. Upon a. given abnormally high temperature condition in compartrnent. 25 which is determined by I:he setting of screw stop 9, contact finger I engages contact finger 5 to close circuit 23 for sounding of the alarm 24. Also upon a given abnormally low temperature condition in compartment 25 which is determined by the setting of screw stop I0, contact finger I engages lower contact finger 6 to close the circuit 23 for sounding of alarm 24. In connection with the foregoing II. should be noted that if operating element I I falls due 130 Fig. 2 by stop 35.

leakage of the gas fill in chamber I6. diaphragm I5 collapses under the action of loading spring I2 and contact finger I is thus moved into engagement with lower contact finger 6 to close the alarm circuit 23 for indication of thls condltion.

As will now be sei; forth, the above described alarm control device is provided with an Off- On" control mechanism which is operable by the adjusting knob 4 of temperature control device 2 to open the alarm circuit 23 under any of the aforementioned abnormal conditions. This coutrol comprises a horizontally disposed leaf spring member 30 having one end fixed within casing 8 and having an inclined cam portion 3I and a downwardly extending leg 32 formed an the free end threof. Member 30 is biased move upwardly into the position shown in Fig. 2 and upon downward movement thereof from such position extension 32 engages lower contact finger 6 to move the same downwardly out of engagement with stop I0 into the position shown in Fig. 3. Also the free end of member 30 is operatively connected to upper contacl: finger spring 33 which is held under compression between the free end of position shown in Fig. tact finger 5 in the position shown in Fig. 3, and said finger is resettable in the position shown in Fig. 2 by a stop 35 associated with bar 20.

Member 30 has a horizontally disposed operating element 36 associated therewith which is slidably supported upon casing 8 and is provided with a downwardly extending projection 31 for engaging cam portion 3 I. Operating element 38 is the right into the position engaged by a projection 40 on knob 4. Projeotion 40 acts upon movement of knob 4 in a counterclockwise direction into I:he alarm 01T position shown in Fig. 2 to m0ve opemting element 36 toward the left er downward dition in chamber 25. Upon movement of knob position bow spring 33 operates as hereinbefore set forth to move upper contact finger 5 into the position illustrated in Fig. 3 and said finger 5 is thus moved out of engagement with contact finger 7 to open the alarm circuit 23. Upon movement of knob 4 out of its alarm off position, upper contact finger 5 is maintained in the position shown in Fig. 3 under the action of bow spring 33 to prevent immediate reestablishment of alarm circuit 23. However, assurning that the temperature in the freezing compartment 25 is reduced, contact finger l returns toward the normal position shown in Fig. 2 and at a predetermined normal temperature condition in said compartment upper contact finger 5 is returnecl to the normal position shown in Upper contact finger 5 is thus reset to provide for reestablishment 01 alarm circuit 23 if the temperature in compartment again rises to an abnormally high value.

Assume now that contact finger l has moved into engagement with contact finger 6 in response 130 an abnormally low temperature coxidition in compartment 25 or in response to failure of gas pressure in chamber I6 ot' operating element II.

Upon movement of knob 4 into alarm oflf" position, contact finger 6 is moved downwardly into the position shown in Fig. 3 to disengage the same from contact finger 1 for opening of the alarm circuit 23. When knob 4 is moved out cf alarm oft position lower contact finger 6 is returned immediately to the position shown in Fig. 2 to provide for re-establishment 01 alarm circuit 23 if operating element II is inoperative or if the temperature in compartment 25 is still at an abnormally low value.

What I claim as new and desire to secure by Letters Patent is:

1. In a refrigerator control system, the combination with a temperature responsive control device for automatically controlling starting and stopping cf a refrigerator to normally maintain the temperature therein within a predeter'minecl working range, said device having a manual adjusting part as sociated therewith for varYing the limits of said working range, cf a temperature responsive alarm control device associate d with said former control device and operable independently thereof to actuate an associated signal in response to an abnormal temperature condition within the refrigerator outside of said working range, said alarm control device being controllable by said adjusting part to render the same imperative to actuate said signal upon movement of said adjusting part into a. given position and to restore the same to operative condition upon movement or said adjusting part out 01 said given position.

2. In a refrigerator control system, the combination with a temperature responsive control device for automatically controlling starting and stopping of a refrigerator to normally maintain the temperature therein within a predetermined working range, said device having a manual adjusting part associated therewlth for varying the limits cf said working range, 01 a, temperature responsive alarm control device assoclated with said forme: device and operable independently thereof to actuate an associated signal in response to an abnormally high temperature condition within the refrigerator which is above said werking range, said alarm control device being controllable by said adjusting part to render the same inoperatiy'e to actuate said signal upon movement cf said adjust ing part into a given position and to restore the same to operative condition upon movement of said adjusting part out o! said given position but only upon restoration of the temperature within the refrigerator to a predetermined value within said working range.

3. In a refrigerator control system, the combination with a. temperature responsive control device for automaticalljr controlling starting and stopping of a refrigerator to normally maintain the temperature therein within a predetermined working range, said device having a manual adjusting part associated therewith for varying the limits of said working range, of a. unitary temperature responslve alarm control device asso'- cia.ted with said former device and operable independently thereof to actuate an associated signal in response to a predetermined abnormally high er a. predetermined abnormaily low temperature condition within the refrigerator. sald alarm control device having control means associated therewith =which is operable by said adjusting part to render the same imperative to actuate said sigma] upon movement of said adjusting part into a gi-ven position and to restore the same to operative condition upon movement of said adjusting part out of said given position.

CLARENCE W. KHN.

RLFERENCES CITED The following references are cf record in the file of this patent:

UNITED STATES PATENTS 

